My month old baby keeps throwing up after every feeding. What could be wrong? Breastfeed during the day, 2 bottles of 2oz newborn formula at night.

Esophageal Reflux. Or gastro-esophageal reflux disease. Occurs when lower esophageal sphincter is loose, doesn't close, stomach content comes up as vomiting. Make sure, when feeding, head 45 degree upright, a good seal while nursing, no gap, so that baby doesn't swallow air. Burp up halfway and after feeding, keep baby upright for 1/2 hour. If not better, anytime projectile vomit, poor wt. Gain, see doc asap.
See Pediatrician. This is not something to try to tinker with at home, call your pediatrician for visit asap as little ones become dehydrated very rapidly. At this age, could be congenital issue, metabolic, pyloric stenosis, infection, others.
Probably reflux . Reflux is very common in babies. Most grow out of it by 6-8 months. If baby not gaining weight/is bringing up all of feedings, that must be addressed by your pediatrician. You don't say how much baby is vomiting. It is often over estimated as a teaspoon of spit up makes a fairly large spot on the blanket- so seems like more. Speak with your doctor as other serious things can be going on.